Tooth staining has many causes. These include the regular use of products that contain staining chemicals or color bodies such as foods, drinks (coffee, tea, cola, wine), or the use of tobacco. In other cases, medications, diseases, and poor dental hygiene may result in tooth staining. Staining affects the aesthetic appearance of teeth, and may also be a contributing factor to tooth decay and loss.
There have been many product formulations developed to prevent or remove stains from teeth. These include bleaches or oxidants, or oxidant free formulations. In the development of these formulations, significant testing is required to show formulation efficacy.
Some of the efficacy testing procedures developed use bovine or human teeth, or ceramic disks or powder specimens. In these procedures, a dental spectrophotometer is used to evaluate the color of the specimens both before and after immersion in the staining solutions (such as tea). Commission internationale de l'éclairage (CIE) L*a*b* color space values are recorded, and the change in color (ΔE*) is calculated. Staining is done either before or after the specimens are treated with the stain prevention or removal formulation. In the case of stain removal testing, the specimens are immersed in the staining solution before the specimens are treated with the stain removal formulation. In the case of stain prevention testing, the specimens are immersed in the staining solution after the specimens are treated with the stain prevention formulation.
In another test procedure, ceramic powder is placed in staining solution either before (removal testing) or after (prevention testing) exposure to the treatment solution. Then, the powder is dissolved away using acid, and the color change in the effluent is measured.
The above methods are labor intensive, and are therefore not high-throughput methods for screening the efficacy of formulations being tested for tooth stain prevention or removal.
What is needed is the development of high-throughput methods for detecting efficacy of tooth stain prevention or removal formulations.